1. Field of the Invention
The invention relates to a load-bearing frame for a conveyor device, in particular a shelf stacking device, with a support frame which can be secured to a lift carriage of the conveyor device and, on it, mutually parallel support mechanisms with displaceable telescopic support arms for a storage unit such as a pallet, box, etc., and a conveyor unit running parallel with a displacement mechanism of the support mechanisms constituting a conveyor direction.
2. The Prior Art
Patent specification DE 100 40 492 A1 discloses a telescopic table system on a load-bearing frame of a shelf stacking device for moving pallets, boxes etc. in or out of shelves, which has a frame with a drive unit and an arm comprising several telescopic elements engaging one inside the other which can be displaced on guide rails, thereby enabling a specific range of the arm be obtained in order to stack in at least two stowage spaces disposed one behind the other.
Also known is a loading table of a lift system with telescopically displaceable load-bearing arms, which is additionally provided with a conveyor system in the region between the load-bearing arms, such as a belt conveyor or chain conveyor. This simplifies the manipulation of storage units when transferring them from upstream or downstream incoming and outgoing conveyor systems, such as belt conveyors, roller tracks, etc.
The objective of the invention is to propose a load-bearing frame, by means of which the running time involved in storing and retrieving items can be reduced.
This objective is achieved by the invention due to the fact that the conveyor system constituting the conveyor unit has two pairs of conveyor mechanisms disposed between the supporting mechanism, which are symmetrically disposed by reference to the mid-plane and extend perpendicular to a standing surface of the shelf stacking device, with a conveyor direction parallel with a displacement direction of the support mechanisms, constituting a linear conveyor, and mean distances of the linear conveyor extending perpendicular to the mid-plane are bigger than a mean distance of the support mechanisms. The surprising advantage of this system is that the storage unit can be transported both longitudinally and transversely and many of the turning mechanisms needed in the receiving and despatching area and the non-productive time incurred by such systems, which would otherwise increase handling times and thus increase warehousing costs, are significantly reduced.
Advantages are also to be had from other embodiments of the load-bearing frame in which load-bearing surfaces of the linear conveyors of the conveyor mechanisms form two parallel conveyor planes at a distance from one another and extend perpendicular to the mid-plane and/or, by reference to a transport plane formed by the load-bearing surface of the conveyor mechanisms, a conveyor plane is formed at a slight distance above the latter whilst the other conveyor plane extends underneath at a distance from it. As result of these embodiments, allowance is made for the different levels of the bottom face by which the storage unit is accommodated, which are determined by the special design of the sub-structure of adjoining storage units depending on the direction in which they are conveyed. The option of being able to convey the storage unit in the direction of longitudinal extension or transversely thereto is made possible by the fact of being able to set the fixed conveyor planes at different levels relative to a transport plane, and whilst maintaining the transport planexe2x80x94in line with the load-bearing surface of the support mechanismsxe2x80x94the conveyor mechanisms and the load-bearing surfaces afforded by the conveyor mechanisms run at a lower level than the transport plane during longitudinal transport and at a higher level during transverse transport, so that there is no need to make any other height adjustment or time-consuming adjustment of other equipment.
Another embodiment of the load-bearing frame is possible, in which the distance between the conveyor planes corresponds to an internal height of a sub-structure of the storage unit, thereby ensuring an exact adjustment to accommodate the structural features of the sub-structure of the storage unit.
In another advantageous embodiment of the load-bearing frame, a mean distance between the linear conveyors constituting the conveyor plane underneath the transport plane is greater than a mean distance of the support mechanisms but shorter than a mean distance of the linear conveyors constituting the conveyor extending above the transport plane, which means that a universal structure may be used for longitudinal transportation and transverse transportation of the storage unit, dispensing with the need for complex positioning mechanisms to adjust the load-bearing frame.
Another advantage is to be had from an embodiment of the load-bearing frame, in which a support device is provided more or less at the centre between the telescopically adjustable load-bearing arms of the support mechanisms, in the form of a roller track or by means of a belt or chain circulating endlessly about a roller system, etc., because this provides central support for the storage unit.
The load-bearing frame can be made in other advantageous embodiments in which the linear conveyors are provided in the form of traction conveyors and/or by chain or belt conveyors or belt drives running across a length of the support frame, which means that tried and tested systems may be used for transporting and manipulating the storage units on the load-bearing frame.
Also of advantage are embodiments of the load-bearing frame in which the linear conveyors are drivingly linked, either jointly or individually, and/or the support mechanisms are linked to one another and drivingly linked to a drive, in particular an electric drive, which reduces the complexity of the mechanical and control system.
In other embodiments of the load-bearing frame, the conveyor planes are provided with rail-type guide elements disposed across the length of the support frame, extending in a direction perpendicular to the conveyor direction and bounding a conveyor width, and/or guide elements are provided in the form of roller tracks or guide rails and act as lateral guides for the storage unit, thereby ensuring that it is centrally positioned on the load-bearing frame incorporating the conveyor mechanisms, which makes the transport process safe and reliable.
In other advantageous embodiments of the load-bearing frame, the guide elements are adjustably supported on the support frame, enabling the guide elements and the conveyor mechanisms to be exactly adapted.
In another embodiment of the load-bearing frame, the telescopic support arms are made up of multiple telescoping systems and/or an adjustment path of the telescopic support arms corresponds to at least twice the amount of a loading depth of the load-bearing frame on either side of a zero position on the support frame, which means that the storage unit can be stored and retrieved from a racking system of double depth designed to provide economic storage facilities.
In other advantageous embodiments of the load-bearing frame, a length of the linear conveyors more or less corresponds to the loading depth of the load-bearing frame and/or opposite ends of the linear conveyors form inclined receiving and despatching areas adjoining transport elements, enabling the storage unit to be placed on the conveyor mechanisms in the region of the load-bearing frame and continuously transferred from the conveyor mechanisms onto the support mechanisms, which increases conveyance speeds, bringing quite a significant reduction in storage operating times.
Other embodiments of the load-bearing frame have a drive for the linear conveyors and/or a drive for the support mechanisms which is reversible, thereby enabling positioning sequences for the storage unit to be run with minimised cycle times, both in the racking and on the load-bearing frame.
Also of advantage is the load-bearing frame in which the drives for the support mechanisms and the conveyor mechanisms are designed so that they can be activated and powered either individually or jointly as an option, via a control system of the shelf stacking system, making economical use of energy.
In yet other advantageous embodiments, the storage unit can be positioned on the exact centre of the load-bearing frame and accurate positioning of the storage unit is guaranteed, which permits high acceleration values and hence conveying speeds, thereby reducing transfer times and the associated warehousing costs.
Finally, in other embodiments of the load-bearing frame, the support frame is made in a lightweight construction from sheet metal sections and/or from lightweight metal, the advantage of which is that the intrinsic weight of the system is reduced and hence the payload factor, calculated as a ratio of payload to intrinsic weight, which has positive implications in terms of efficient use of energy in operating such systems, which is further enhanced by the shorter transfer times resulting from the fact that the weights which have to be moved are lower.